Tandem yarn winding

ABSTRACT

Method and apparatus for tandem yarn winding filamentary structures, such as filaments or yarn, onto a plurality of bobbins in such a manner so as to substantially preclude the migration of finish from one filamentary structure to the other. A traversing guide conducts each pair of yarn onto the surface of the drive roll. The yarns pass around at least a portion of the surface of the drive roll before being wound on the bobbins which are driven by the drive roll. Each bobbin is mounted on a chuck which is movable on a carriage, preferably along a straight path toward and away from the drive roll. As the yarn package builds, the axis of rotation of each bobbin progressively moves away from the drive roll. A cam and follower associated with the carriage imposes a predetermined resistance to movement of the carriage, thereby maintaining a suitably programmed force between the bobbin and the drive roll throughout the winding process, which force is necessary to build stable and well-formed yarn packages.

United States Patent Sistare et al.

[ 5] Feb. 15, 1972 [54] TANDEM YARN WINDING [72] inventors: Vann M. Sistare, Rome, 6a.; Kenneth Brooks, Charlotte, N.C.

[73] Assignee: Celanese Corporation, New York, N.Y.

[22] Filed: Dec. 30, 1969 [2l] Appl. No.: 889,209

Primary Examiner-Stanley N. Gilreath AttomeyThomas J. Morgan, Stephen D. Murphy and Andrew F. Sayko, Jr.

[57] ABSTRACT Method and apparatus for tandem yarn winding filamentary structures, such as filaments or yarn, onto a plurality of bobbins in such a manner so as to substantially preclude the migration of finish from one filamentary structure to the other. A traversing guide conducts each pair of yarn onto the surface of the drive roll. The yarns pass around at least a portion of the surface of the drive roll before being wound on the bobbins which are driven by the drive roll. Each bobbin is mounted on u chuck which is movable on a carriage, preferably along a straight path toward and away from the drive roll. As the yarn package builds, the axis of rotation of each bobbin progressively moves away from the drive roll. A cam and follower associated with the carriage imposes a predetermined resistance to movement of the carriage, thereby maintaining a suitably programmed force between the bobbin and the drive roll throughout the winding process, which force is necessary to build stable and well-formed yarn packages.

10 Claims, 6 Drawing Figures 4 7a 76 74 so 6 a o o 0 a 0 64 l I 64 56 o o 2 A9 a 24 'I 54 E- HQ 0 64 0 L+ a I 64 o 9 11 n T62 i 7 to one a Q. I I, 0 0:0 66 E @l, a 78 6 7 o 19 a o 74 o o o o 3 a Q o o 0 o 0 0 0 O PATENTEHFEB I 5 I972 I 3.642.217 sum 2 [1F 4 TANDEM YARN WINDING BACKGROUND OF THE INVENTION This invention relates to methods and apparatus for winding filamentary structures, and more particularly to winding a plurality of filaments, threads or yarns into separate packages.

Conventionally, yarn is extruded through a spinneret and passed around feed rolls onto a bobbin driven by surface contact with a revolving drive roll operating at the same surface speed. One or more rotary bobbin chucks are positioned adjacent to the drive roll and are movable toward and away from the surface of the drive roll. In the case of conventional tandem winding where two bobbins are driven by a single drive roll, the second chuck is generally spaced around the circumference of the drive roll from the first chuck. Multiple ends of yarn are simultaneously positioned against the periphery of the first bobbin by a traverse mechanism. The yarn end to be wound on the first bobbin travels through the nip between the bobbin and the drive roll and continues around the first bobbin. The yarn for the second bobbin is first passed along the surface of the first bobbin, then passes through the nip between the first package and the drive roll where it separates from the first yarn end and continues along the surface of the drive roll before reaching the nip of the second bobbin and being wound on the second bobbin.

ln manufacturing synthetic yarns, finishes are applied to the freshly spun filaments to facilitate the operation of winding up the filaments and any subsequent textile processing steps. As the filaments emerge from the spinneret and are rapidly solidified as they pass through the surrounding atmosphere in the spinning column before reaching the windup bobbin, the yarns are commonly passed in contact with a liquid finish. The textile properties of the filamentary material and the success with which they may be processed in subsequent operations such as drawing and beaming depends to a great extent on the presence of a correct amount of finish. It is accordingly essential that the weight of finish per unit length of yarn be substantially uniform and equal on all the yarn ends.

Moreover, variations or an incorrect amount of finish applied to the filamentary strands adversely effects the uniformity of the yarn layers in the package. In the an of winding up yarn, it is well known that the quality of package construction or build" is extremely important in yarn processing operations. Improperly constructed or built packages are characterized by such faults as bulges at the package edges, insufficient or too great a density, a saddle-shaped periphery, loose or dropped ends protruding from the packages sides, and the like. These faults, when they are not kept to a minimum, make the packages useless. For instance, packages that are too soft often collapse before winding of the package is completed. Such a collapse is caused by the lack of stability of the inner layers of the yarn package which have to support the continuously increasing number of outer layers. Packages that are excessively dense subject the yarn to undesirable stresses, particularly at the package sides where density is the greatest, thus adversely affecting the uniformity of yarn properties. Saddle-shaped packages and packages having dropped ends invariably lead to poor yarn Winding and varying yarn takeup tensions that interfere with the required uniformity in subsequent operations such as drawing, beaming, knitting or weaving.

It is also well known that the process of building good yarn packages is an extremely delicate operation and must be isolated from a number of outside influences. This involves a continuous and delicate balance of proper machine design and proper machine setup. Of all the parameters involved, the correct amount of finish on the yarn is of the utmost importance. Too little finish causes unwinding difficulties and excessive friction when the yarn passes over the many guides and contact surfaces during subsequent operations. Too much finish adversely effects package stability which leads to bulging sides and collapsed packages.

A particular example where the pairs of yarn ends inherently and consistently contain substantially different levels of finish and variations in finish level along the length of the yarn. is the tandem winding method described in US. Pat. No. 2,647,697. As described in this patent, the pair of takeup cylinders or bobbins is arranged such that one cylinder is positioned vertically above the other. After both yarns have passed through the traverse guide, the yarn destined for the lower bobbin or core contacts the upper bobbin and passes around a portion of the upper bobbin and then parts from the yarn which is wound onto the upper bobbin, passing around a portion of the drive roll and is then wound up on the lower bobbin. In this case, the yarn on the upper bobbin steals finish in a random manner from that on the lower bobbin, thus acting in a manner similar to a blotter. As a consequence, the upper bobbin may contain up to twice the amount of finish when compared with the lower bobbin, leading to package building difficulties and poor processing of the yarn in subsequent operations.

The difference in the resultant finish levels between the two yarn ends may be substantially compensated for by applying corrected differential amounts of finish to the running yarn ends, such as described in US. Pat. No. 3,421,926. However, the success of this method depends upon the uniformity of finish loss or gain of the respective yarn ends. It is accordingly desired to develop a more predictable and accurate method of finish control to insure a substantially uniform finish level in a high-speed commercial scale process.

In making synthetic yarns by spinning or other processes, a large number of yarns are produced simultaneously. These yarns must be wound individually on bobbins. Since floor space is usually limited, it is desirable to group the bobbin winding stations as closely together as possible. Also, it is advantageous to reduce the bulk of the machinery wherever possible. Such a reduction of the bulk of the machinery substantially reduces the cost of the equipment required for the winding of yarn packages.

Another difficulty with conventional winding apparatus is that the bobbin chucks must be positioned close to the drive roll. When there are several chucks driven by a single drive roll, and when it is desired to wind large packages, there is insufficient space to swing the chuck arm to a position where the filled bobbin can be readily removed from the chuck. In a typical installation, there are a great many bobbins being wound simultaneously and in order to minimize labor time, the bobbin chucks should be readily accessible and the bobbins should be easily removed from the chucks.

OBJECTS OF THE INVENTION Accordingly, it is an object of this invention to provide a tandem yarn takeup in which the finish migration from one yarn to another to produce nonuniform finish levels is substantially minimized.

A further object of this invention is to provide a tandem yarn takeup for winding multiple bobbins utilizing a single drive roll while maintaining substantially the same quantity of finish on the yarn in each bobbin.

A still further object of this invention is to provide a yarn takeup that imparts a programmed contact force between the yarn bobbins and the drive rolls for building of stable packages of high quality.

A still further object of this invention is to provide a method and apparatus for winding large packages in a minimum amount of space.

Another object of this invention is to provide a method and apparatus for winding bobbins in which the filled bobbins may be removed and empty bobbins inserted readily.

Yet another object of this invention is to provide a method and apparatus for winding bobbins that is low in cost and easy to maintain and operate.

SUMMARY OF THE INVENTION These objects are accomplished in accordance with a preferred embodiment of this invention by a yarn takeup in which a pair of yarns having a liquid finish thereon pass through a common traversing guide positioned adjacent a drive roll, causing both yarns to be deposited and printed on the drive roll. A pair of chucks, one upper and one lower bobbin chuck, are mounted on carriages for movement toward and away from the drive roll. Each carriage is mounted on a pair of bars for sliding movement along a straight path. Bobbins on the chucks engage the surface of the drive roll and one yarn end passes from the drive roll onto one bobbin while the other yarn end continues around the surface of the drive roll and then passes onto the second bobbin.

Three or more bobbin chucks may be utilized to take up three or more yarns in practicing this invention. The only theoretical limitation on the number of chucks is the practical limitation dictated by the geometry of the takeup apparatus.

The plurality of yarns are printed directly onto the surface of the rotating drive roll and passed around at least a portion of the periphery of the drive roll, preferably at least one radian or about percent of the periphery and most preferably at least about 25 percent. Thus, the yarn contacts the drive roll prior to the bobbin. This first point of contact with a rotating surface of the takeup, here the drive roll, is on the drive roll side of a tangent to the point of initial contact with the rotating surface of the takeup, e.g., line 7-7 in FIG. 1. In addition to building uniform packages, passing the plurality of yarns around a portions of the periphery of the drive roll appears to have the effect of leveling the amount of finish on the yarns when the finish levels differ because of occasional nonuniformities in finish application.

During package development, one of the important parameters is the magnitude of the force with which the package is pressed against the bobbin drive roll. It was discovered that regardless of the wide range of the slopes tested, the package would usually collapse well before the full diameter was achieved when a gradually diminishing force was utilized. After many trials, quite surprisingly, it was discovered that package stability could be obtained when the chuck loading is gradually increased from the initial, unusually high loading, e.g., 7 pounds, to a higher loading, e.g., 8 pounds, when a small amount of yarn, e.g., about 1 /2 inches, accumulated on the bobbin. From that point, the loading is decreased gradually, e.g., to about 3 pounds when about 3 /2 inches of yarn accumulated on the bobbin. During the final part of the winding operation, the loading is further decreased, e.g., to about 2V2 pounds final loading corresponding to a 4-inch layer of yarn on the bobbin and ultimate package diameter of about 12 inches.

While there is no certain explanation for the unusual chuck loading profile that produces packages giving substantially straight sides and exceptional stability, one speculative explanation is that the initial high chuck loading is required for providing a stable base for the remaining yarn layers. The middle portion of the profile represents the effort to reduce as quickly as practical the force between the package and bobbin drive roll to prevent collapse. The third and final slope in the curve covers that part of the winding in which only a minimal force between package and the roll is used; sufficient only for good frictional contact that precludes the slippage of bobbins on the drive roll.

A great variety of chuck loading profiles are encountered on commercial yarn takeup machines and proprietary machines developed by synthetic yarn manufacturers. Generally, these profiles descend gradually, although in some cases they are found to be somewhat ascending, or to be more or less constant. In these cases, when the slope of the curve varies as the package builds, this variation can invariably be traced to the changing geometrical relationship of the parts inherent in the mechanical construction of the mechanism.

As the package builds on the upper and lower chucks, the carriages move away from the drive roll along the carriage path. Each carriage has a cam in position to engage a follower on the frame of the machine. The cam follower is spring biased against the cam and the profile of the cam is such that the follower resists longitudinal movement of the carriage along the path away from the drive roll. The resisting force varies in a prescribed proportion to the diameter of the yarn,

package so that the pressure of the yarn package against the bobbin drive roll is controlled in a programmed manner, as previously described. When the bobbin is filled, the carriage can be displaced to the outer end of its path by means of a handle, where the bobbin can be readily removed and replaced with an empty bobbin.

In order to conserve space and equipment costs, the apparatus of this invention includes a central cam shaft having a plurality of traverse cams at spaced intervals for operating the traverse guides which are positioned at opposite sides of the cam shaft. Each traverse guide is part of a winding station on each side of the cam which includes a drive roll, a pair of bobbin chucks and their respective carriagesEach traverse cam thus serves four bobbin chucks and the cam shaft has a plurality of traverse cams at spaced intervals along its length. Duplication of the traverse cam at each winding station is thus avoided.

DESCRIPTION OF THE DRAWINGS The preferred embodiment is illustrated in the accompanying drawings wherein:

FIG. 1 is a cross-sectional view of the tandem yarn takeup apparatus along the line 1-1 of FIG. 2;

FIG. 2 is a front elevational view of the apparatus of this invention;

FIG. 3 is a cross-sectional view of the apparatus along the line 33 in FIG. 2, showing the feed rolls and yarn finish applicators;

FIG. 4 is an elevational view, partially in cross section, of the apparatus along the line 4-4 in FIG. 1 showing the traverse guide and cam;

FIG. 5 is a cross-sectional view of the apparatus along the line 5-5 in FIG. 4; and

FIG. 6 is a cross-sectional view of the apparatus along the line 6-6 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, the apparatus of this invention includes an upright frame which has a substantial length. At suitable intervals along the length of the frame, there are central support members 8 and intermediate casting 2. Plates 6 project outwardly from central supporting members 8 and castings 2. Between each pair of plates there are two winding stations indicated generally at 4 in FIG. 2. As shown in FIG. 1, these winding stations are provided on both the front and rear side of the frame.

Each winding station includes a bobbin drive roll 10 and a traverse guide 24 associated with each drive roll 10. Each traverse guide 24 conducts a pair of yarns onto the surface of the drive roll 10 in a reciprocal fashion. The drive roll thus serves as a print roll upon which the yarn is laid by the traverse guide. The yarn is carried to the bobbins 56 and 58 on the drive roll and is deposited or printed onto the bobbins. Although the term yarn is used herein to describe the filamentary structures that are useable with this apparatus, yarn is intended to include monofilaments, yarns, threads, strands and similar structures.

The yarns may be prepared from natural materials such as wool, cotton or silk or they may be synthetic materials prepared from cellulose derivatives such as cellulose acetate or from other polymeric materials including viscose, acrylonitrile polymers, polyamides, polyesters, polyesteramides or vinyl polymers such as vinyl choride polymers. Likewise, filaments from inorganic materials, such as metallic wires, may be wound utilizing the apparatus and method of this invention.

The filaments process may vary widely in size. For example, cellulose acetate yarns from about 40 to 300 denier have been wound successfully by the process and apparatus of this invention. The yarns may be wound up at high speeds, preferably from about 50 to 1,500 meters per minute. The process and apparatus of this invention may, of course, be utilized in connection with drawing processes and machines. The various parts of the apparatus may be made of any appropriate material, such as metals, alloys, plastic, glass, enamels, etc.

As shown in FlGS. 2 and 3, yarns 14 are conducted over guides 16 on opposite sides of the frame. From the guides 16 the yarns pass over lubrication applicators l8 and are wrapped once on a feed roll 20. After passing through guides 22, the yarns 14 are led through a traverse guide member 24 (FIG. 4) which is mounted for reciprocating movement between a pair of guide rails 26. Rails 26 are removably mounted in plate 12. Preferably a pair of yarns 14 pass through individual slots in the guide member 24. The integrity and quality of the yarn package is enhanced by positioning the traverse guide member 24 in close proximity to the drive roll 10.

Reciprocating movement of the guide member 24 is accomplished by cam 28. A follower on the guide member 24 cooperates with a groove 30 in the peripheral surface of the cam to cause movement of the member 24 back and forth along the length of the guide rails 26. Pillow blocks 32 are provided on central supports 8 and castings 2 at spaced intervals along the length of the frame. Bearings 34 in these pillow blocks support a rotary cam shaft 36. Each traverse cam 28 has a hub 38 with a radial flange 40 at one end. A collar 42 is fixed on the shaft adjacent to the opposite end of the hub 38 and a coiled spring 44 between the collar 42 and the hub 38 urges the hub of the left cam toward the right as viewed in FIG. 4. A clutch collar 46 is also fixed on the shaft 36 and includes a radial flange. When the opposing surfaces of the hub flange 40 and the flange of the collar 46 are in engagement with each other, the traverse cam 28 turns with the shaft 36. A clutch release device, indicated generally at 48, is operated by a rotary handle 50 to separate the hub flange 40 from the clutch flange 46, thereby disengaging the cam 28 from shaft 36. The left-hand cam 28 in FIG. 4 is shown in its disengaged position.

The clutch release device 48 is equipped with a high friction breaking surface to quickly arrest the rotation of cam 28 when the hub flange 40 is separated from the clutch collar 46. When the cam is stopped, removable rails 26 can be lifted out of plate 12 and a new rail and guide assembly can be positioned in their place. The removable guide assembly insures that preassembled units, properly adjusted, lubricated and inspected, can be installed on the apparatus by operators having little or no mechanical training. Such assemblies can be prepared when it is convenient and stored in the operating area until required for the replacement of worn or damaged units.

As shown in FIGS. 1 and 5, the cam 28 drives traverse members 24 on both the front and the rear of the machine frame. These members 24 guide the yarn onto the surface of the respective drive rolls 10, but if it should be necessary to service the machine at one station 4, by turning the handle 50, the cam 28 can be quickly stopped, without affecting the other cams along the length of the shaft 36.

Each drive roll is positioned at the side of a plate 6 and is journaled in bearings for rotation. Preferably, the rolls 10 are mounted on a common axle which projects outwardly on opposite sides of the plate 6. Rotation is imparted to the drive rolls 10 by countershafts 52 which extend along the length of the frame and by endless timing belts 54 which engage sprockets on the countershafts 52 and the drive gear belt pulleys.

The yarn 14 is wound on a bobbin that is supported on an upper bobbin chuck 56 and lower bobbin chuck 58, respectively. As used herein, the term bobbin" includes hollow cylindrical cores on which yarns are typically wound to form yarn packages. The bobbin chucks 56 and 58 are supported for rotation on carriages 60 and 62, respectively. Each carriage is mounted on a pair of bars 64 for movement along a straight path toward and away from the drive roll 10. The lower carriage 62 has a cam 66 with a cam surface 68 projecting downwardly. A similar cam plate 70 with a cam surface 72 is provided on the upper carriage 60. A pivoted cam follower 74 engages the respective cam surfaces 68 and 72. A tension spring 76, which is connected between a bracket 78 on the plate 6 and a pin 80 on the follower 74, urges the follower against the cam surface.

The contact force between the drive roll 10 and the surface layer of yarn on the bobbin affects the manner in which the package is built. If the contact pressure is too low, insufiicient torque is transmitted to the bobbin, so that slippage between the bobbin and the drive roll occurs and the yarns are not properly positioned in the package. If the contact force is too high, the package may be deformed and the package sides will be bulged.

As shown in FlG. l, the profile of each surface 68 and 72 is such that the follower 74 exerts a force on the carriage which is generally toward the center of the machine frame. However, as the carriage moves away from the drive roll 10, such as while the yarn package builds, the follower passes over a point of inflection, which reverses the direction of the force on the carriage, thereby displacing the carriage away from the drive roll 10. An adjustable stop 82 on the plate 6 prevents the follower from swinging beyond a predetermined position after the carriage has moved out of engagement with the follower 74. Each carriage 60 and 62 is also provided with a handle 84 to allow sliding movement of the carriage manually along the bars 64.

The winding stations 4 at the rear of the machine are aligned with stations provided at the front of the machine, as shown in FIG. 1. The use of a common cam 28 for controlling the traverse guides 24 for each drive roll reduces the amount, space and cost of machinery that otherwise would be required. Also, winding a pair of bobbins from a single drive roll at the front and at the back of the machine further minimizes space and apparatus requirements. The machine of this invention is generally modular in construction so that additional winding stations can readily be provided merely by extending the length of the machine and duplicating the winding stations.

In operation, a pair of yarns is laced through the yarn guides 16 from around the feed roll 20 and through the slot in the traverse member 24 and is wrapped from the back and under the drive roll 10. One yarn end is wound on a bobbin on the lower chuck 58 while the other end is wound on a bobbin on the upper chuck 56. Each carriage is displaced along the rods 64 until the yarn on the bobbin surface engages the surface of the drive roll 10. When winding starts, the carriages 60 and 62 are adjacent the inner end of the rods.

Rotation is imparted to the drive rolls 10 by the shafts 52 and to the traverse cams by the shaft 36, which causes the yarn ends to be partially wrapped in a changing helical-type pattern on the drive rolls 10. Both yarn ends pass through the nip between the lower bobbin chuck 58 and the surface of the drive roll and one of the yarn ends passes through the nip between the upper bobbin chuck 56 and the drive roll and both are wound or printed on their respective bobbins.

Because the yarn end for the bobbin on the upper chuck 56 passes instantaneously through the nip between the bobbin on the lower chuck 58 and does not pass around a portion of the lower bobbin, no detectable robbing of finish onto the lower bobbin occurs. Therefore, there is no significant migration of finish from one yarn end to the other and both ends preserve the original and very nearly equal amount of finish.

As the winding process progresses, the diameter of the yarn package increases, forcing the carriage away from the center of the machine. The cam surfaces 68 and 72 are shaped to provide a suitably programmed contact force between the yarn on the outer peripheral surface of the yarn package and the surface of the drive roll. When the yarn package reaches its maximum diameter, the follower 74 passes over the crest of the cam surface 68 and 72, so that the follower 74 urges the carriage outwardly from the center of the machine and since the yarn on the bobbin no longer engages the surface of the drive roll 10, rotation of the bobbin stops. Of course, conventional brake means may be incorporated in the bobbin chuck for quickly stopping rotation of the bobbin. By grasping the handle 84, the carriage 60 or 62 can be pulled by the operator to its outermost position. The filled bobbin can then be readily replaced with an empty bobbin and the carriage returned to its innermost position so that the winding process can begin again.

Since the carriages are mounted on horizontal bars, the contact force between the yarn in the package and the print roll are independent of gravity, unlike the swinging arm arrangements of conventional winding systems. Also, the contact force can readily be programmed by replacing the spring 76 with another spring of a different spring force, or by varying the profile of the cam surfaces 68 or 72.

EXAMPLE 1 Continuous filament yarns 14 consisting of secondary cellulose acetate having a total denier of 55 and containing 15 filaments were passed over lubricant applicators 18 which were supplied with a uniform amount of finish such that about 3 percent finish was applied to the running lengths of yarn. The yarns were then passed through traverse guide 24, around feed roll 20, as shown in FIGS. 2 and 3, around the lower side of drive roll 10. The yarn ends passed around the drive roll 10 and onto bobbins 58 and 56 respectively at a speed of about 724 meters per minute. Six cells producing a total of 12 ends of yarn were run with bottom bobbins 58 taking up the ends from the even numbered positions (2, 4, 6, 8, l and 12) and top bobbins 56 taking up the ends from the odd numbered positions (1, 3, 5, 7, 9 and 11). This procedure was then repeated to produce l2 more ends of yarn. The finish applied to the yarn consisted of:

59 S.U.V. mineral oil dibutyl ethanolamine salt of oleyl phosphate oxidized soybean oil diethanolamide of coconut oil fatty acids EXAMPLE 2 Runs 1 and 2 of Example l were repeated except that the lace-up of the takeup was reversed. The bottom or first bobbins 58 took up the even position and the top or second bobbins 56 took up the odd positions.

The amount of lubricant based on the yarn applied to each filament in both runs 1 and 2 of the standard lace-up and Example 2 is shown in Table 1 below.

TABLE I Example 1 Example 2 (standard laceup) (reversed laceup) Top Bottom Top Bottom position position position position (even Nos.) (odd Nos.) (odd Pos.) (even Pos.)

1st run 2. 74 2. 70 3. 22 3. 16 2. 76 2. 6S 2. 97 3. 19 2. 91 3. 02 3. 22 3. 30 2. 97 2. 66 3. 06 3. 38 2. 81 2. 94 3. 28 3. 30 3. 17 2. 92 3. 42 3. 43 x=2 89 x=2.82 x=3 20 x=3.30

2nd run 2. 75 2. 74 3. 3. 16 2. 76 2. 64 2. 97 3. 2. 96 2. 95 3. 38 3. 37 3. 03 2. 80 3. 00 3. 2. 83 2 98 3.33 3. 25 3. 22 3. 14 3. 39 3. 56 x=2.02 x=2.99 x==3.19 x=3.30

The packages produced in the preceding examples had an ultimate package diameter of about 12 inches. The programmed force profile between the bobbins and the drive roll was as follows:

Initial Force-about 7 pounds After about 1% in. of yamincreased to about 8 pounds After about 3 /2 in. of yam-decreased to about 3 pounds After about 4 in. of yamdecreased gradually to about 2 pounds The predetermined force profile preferably gradually increases from the initial high loading of from about 5 to 9 pounds to from about 6 to 10 pounds when from about 5 to 20 percent of the desired package diameter is achieved; decreasing the loading to about 2 to 5 pounds when from about 20 to 30 percent of the package diameter is achieved; and finally decreasing the loading to from about i to 4 pounds after at least about 30 percent of the package diameter is achieved.

What we claim is:

1. A process for winding a plurality of travelling continuous filament yarns containing a yarn finish onto at least two separate bobbins comprising:

contacting a plurality of travelling continuous filament yarns with a liquid finish;

guiding a plurality of said yarns to the surface of a rotating drive roll;

surface driving a first bobbin on the rotating drive roll; surface driving at least a second bobbin on said rotating roll, said bobbins being spaced from each other around the periphery of said drive roll;

printing the yarns directly onto the surface of said rotating drive roll, passing said yarns around at least a portion of the periphery of said drive roll; separating at least one of said yarns from said plurality and passing this yarn to the first bobbin and winding it thereon; passing the remaining yarn through the nip formed by said first bobbin and said drive roll and then through the nip formed by a second bobbin and said drive roll; winding at least one remaining yarn on said second bobbin;

said yarns progressively displacing said first and second bobbins away from said drive roll as the yarn packages build;

simultaneously applying a predetermined force to said bobbins against said drive roll, resisting said displacement and maintaining a predetermined force profile between the bobbins and the drive roll throughout the winding process.

2. The process of claim 1 wherein yarn winding is conducted on three separate bobbins.

3. The process of claim 1 wherein yarn winding is conducted on two separate bobbins.

4. The process of claim 1 wherein the yarns pass around at least about 15 percent of the periphery of the drive roll before at least one of said yarns is passed to the first bobbin.

5. Yarn takeup apparatus comprising:

a drive roll, means supporting said drive roll on a frame for rotation, a first bobbin chuck, at least a second bobbin chuck, means supporting said first and second chucks for rotation about an axis spaced from each other and substantially parallel to the axis of rotation of said drive roll;

means for guiding said chucks along a substantially straight path relative to said drive roll, means for guiding a plurality of yarns directly to the surface of said drive roll, and means for biasing said chucks along said path toward said drive roll, whereby a predetermined force is applied while winding yarn ends separately from said drive roll onto said first and second bobbins.

6. The yarn takeup apparatus according to claim 5 wherein said biasing means includes a cam and a follower, movement of said one chuck away from said drive roll causing predetermined relative movement between said cam and said follower, and compression spring means resisting said relative movement, whereby a predetermined biasing force is applied to said chuck corresponding to movement of said chuck.

7. The yarn takeup apparatus according to claim wherein said supporting means includes a carriage supporting said first bobbin chuck and a carriage supporting said second bobbin chuck, said carriages each having a cam secured thereon, first and second cam followers mounted on said frame in position to be engaged by the respective cams on said carriages, and compression spring means resisting relative movement between said cam and follower, whereby a predetermined biasing force is applied independently to the carriages corresponding to their positions along said path.

8. The yarn takeup apparatus according to claim 5 including traversing guide means adjacent said drive roll, said first chuck being movable along said path into engagement with said drive roll at first location, said second chuck being movable along said path into engagement with said drive roll at a second location, said first location being spaced with respect to the peripheral surface of said drive roll between said second location and said traversing guide means.

9. The yarn takeup apparatus according to claim 8 wherein said traversing guide means is positioned to direct said yarns onto said drive roll surface at a location spaced from said first engagement location a distance at least about percent of the periphery of said drive roll surface.

10 Apparatus for winding a plurality of yarns on individual bobbins comprising:

a first drive roll, means mounting said first drive roll for rotation on a frame, at least a second drive roll, means mounting said second drive roll on said frame for rotation about an axis substantially parallel to the axis of said first drive roll, said drive rolls each having a yarn supporting surface,

a rotatable cam between said first and second drive rolls, a yarn guide adjacent said surface of each drive roll, each guide including follower means cooperating with said cam for reciprocating said guide axially across said drive roll,

a pair of bobbin support means associated with each drive roll, said support means being mounted for rotation on said frame, each pair of said support means being movable relative to said frame along a path toward and away from their respective drive roll, said support means for each pair of bobbins engaging a respective drive roll surface at first and second locations, respectively, said first location being spaced with respect to said peripheral surface between said second location and said yarn guide, and means urging each said support means toward a respective drive roll with a force varying in response to displacement along said path. 

1. A process for winding a plurality of travelling continuous filament yarns containing a yarn finish onto at least two separate bobbins comprising: contacting a plurality of travelling continuous filament yarns with a liquid finish; guiding a plurality of said yarns to the surface of a rotating drive roll; surface driving a first bobbin on the rotating drive roll; surface driving at least a second bobbin on said rotating roll, said bobbins being spaced from each other around the periphery of said drive roll; printing the yarns directly onto the surface of said rotating drive roll, passing said yarns around at least a portion of the periphery of said drive roll; separating at least one of said yarns from said plurality and passing this yarn to the first bobbin and winding it thereon; passing the remaining yarn through the nip formed by said first bobbin and said drive roll and then through the nip formed by a second bobbin and said drive roll; winding at least one remaining yarn on said second bobbin; said yarns progressively displacing said first and second bobbins away from said drive roll as the yarn packages build; simultaneously applying a predetermined force to said bobbins against said drive roll, resisting said displacement and maintaining a predetermined force profile between the bobbins and the drive roll throughout the winding process.
 2. The process of claim 1 wherein yarn winding is conducted on three separate bobbins.
 3. The process of claim 1 wherein yarn winding is conducted on two separate bobbins.
 4. The process of claim 1 wherein the yarns pass around at least about 15 percent of the periphery of the drive roll before at least one of said yarns is passed to the first bobbin.
 5. Yarn takeup apparatus comprising: a drive roll, means supporting said drive roll on a frame for rotation, a first bobbin chuck, at least a second bobbin Chuck, means supporting said first and second chucks for rotation about an axis spaced from each other and substantially parallel to the axis of rotation of said drive roll; means for guiding said chucks along a substantially straight path relative to said drive roll, means for guiding a plurality of yarns directly to the surface of said drive roll, and means for biasing said chucks along said path toward said drive roll, whereby a predetermined force is applied while winding yarn ends separately from said drive roll onto said first and second bobbins.
 6. The yarn takeup apparatus according to claim 5 wherein said biasing means includes a cam and a follower, movement of said one chuck away from said drive roll causing predetermined relative movement between said cam and said follower, and compression spring means resisting said relative movement, whereby a predetermined biasing force is applied to said chuck corresponding to movement of said chuck.
 7. The yarn takeup apparatus according to claim 5 wherein said supporting means includes a carriage supporting said first bobbin chuck and a carriage supporting said second bobbin chuck, said carriages each having a cam secured thereon, first and second cam followers mounted on said frame in position to be engaged by the respective cams on said carriages, and compression spring means resisting relative movement between said cam and follower, whereby a predetermined biasing force is applied independently to the carriages corresponding to their positions along said path.
 8. The yarn takeup apparatus according to claim 5 including traversing guide means adjacent said drive roll, said first chuck being movable along said path into engagement with said drive roll at first location, said second chuck being movable along said path into engagement with said drive roll at a second location, said first location being spaced with respect to the peripheral surface of said drive roll between said second location and said traversing guide means.
 9. The yarn takeup apparatus according to claim 8 wherein said traversing guide means is positioned to direct said yarns onto said drive roll surface at a location spaced from said first engagement location a distance at least about 15 percent of the periphery of said drive roll surface.
 10. Apparatus for winding a plurality of yarns on individual bobbins comprising: a first drive roll, means mounting said first drive roll for rotation on a frame, at least a second drive roll, means mounting said second drive roll on said frame for rotation about an axis substantially parallel to the axis of said first drive roll, said drive rolls each having a yarn supporting surface, a rotatable cam between said first and second drive rolls, a yarn guide adjacent said surface of each drive roll, each guide including follower means cooperating with said cam for reciprocating said guide axially across said drive roll, a pair of bobbin support means associated with each drive roll, said support means being mounted for rotation on said frame, each pair of said support means being movable relative to said frame along a path toward and away from their respective drive roll, said support means for each pair of bobbins engaging a respective drive roll surface at first and second locations, respectively, said first location being spaced with respect to said peripheral surface between said second location and said yarn guide, and means urging each said support means toward a respective drive roll with a force varying in response to displacement along said path. 